//The MIT License
//
//Copyright (c) 2009 nodchip
//
//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:
//
//The above copyright notice and this permission notice shall be included in
//all copies or substantial portions of the Software.
//
//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//THE SOFTWARE.
package tv.dyndns.kishibe.server.util;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ParallelComputation {
	private static List<ParallelComputation> instances = new ArrayList<ParallelComputation>();

	public static final ParallelComputation createInstance() {
		final ParallelComputation instance = new ParallelComputation();
		instances.add(instance);
		return instance;
	}

	public static void exit() {
		for (ParallelComputation instance : instances) {
			instance.executorService.shutdown();
		}
		instances.clear();
	}

	private ParallelComputation() {
	}

	private static final int numberOfThreads = Runtime.getRuntime().availableProcessors();
	private final ExecutorService executorService = Executors.newFixedThreadPool(numberOfThreads);

	public boolean execute(List<Callable<Void>> tasks) {
		try {
			executorService.invokeAll(tasks);
			return true;
		} catch (Exception e) {
			return false;
		}
	}

	public int getNumberOfThreads() {
		return numberOfThreads;
	}
}
